What was the contributions of gregorio zara in the field of electricity?

Zara made a huge number of breakthroughs and achievements in the field of electricity. According to About.com, Zara's most notable achievements include:

• Inventing the two-way television telephone (videophone) in 1955

• Discovering the physical law of electrical kinetic resistance (known as the Zara effect) in 1930

• Inventing an airplane engine that was fueled by pure alcohol in 1952

• Improving methods for producing solar energy, including designing a solar water heater, a sun stove and a solar battery during the 1960s

• Inventing a propeller cutting machine in 1952

• Helping with the design of the robot Marex X-10, which was capable of talking, walking, and obeying commands

In 1954, Zara's alcohol-fueled airplane was successfully tested and flown at the Ninoy Aquino International Airport in Manila.